Effects of age and study repetition on recognition memory

In two experiments, the effects of repetition and age on recognition memory were examined using the dual-process framework. According to dual-process models of memory, two processes underlie performance: familiarity and recollection. Familiarity is fast-acting and relatively automatic, whereas recollection requires more time and attention. Research suggests that while familiarity remains intact with age, recollection declines (Yonelinas, 2002). In Experiment 1a, young and older adults' recognition performance was assessed using a plurality discrimination task (Hintzman, Curran, & Oppy, 1992), in which words were presented once, twice, four times, or eight times. All participants displayed a false alarm pattern of an initial increase with increased presentation frequency (1 to 2), then a decrease with further repetitions (4 to 8). Young adults, however, were more successful in reducing false recognition at high presentation frequencies (4 to 8) than older adults. These results not only confirmed a recollection deficit in old age, but also revealed a novel finding---recollection difficulty in young adults when presentation frequency is very low. In Experiment 1b, task demands were changed in the plurality discrimination task so that memory judgments could be made solely based on familiarity. Age differences observed in Experiment 1a were eliminated. These results therefore lend support to the hypothesis that familiarity remains intact in old age. In Experiment 2, possible age-related difference in the encoding of perceptual details for repeated items was examined. DiGirolamo and Hintzman (1997) found that young adults do not always notice changes in an object over presentations. However, their results did not replicate with the plurality discrimination task in young or older adults. Therefore, encoding deficits might not be the cause of age-related differences observed in repetition and aging studies. A second goal of the present study was to examine the neuropsychological correlates of age differences in recognition memory. Correlational analyses revealed a significant relationship between frontal lobe function and age differences presumably due to recollection deficit. Implications of these results are discussed in detail in context of the dual-process models of memory.